For this teacher, summer was an adventure halfway across U.S.

Most teachers relax during the summer. Not Deer Park School’s Dan Block. He rode his bike 1,739 miles from his garage in Columbia Falls to his parents’ home in Watertown, Wis.

This was no slow-paced-enjoy-the scenery journey, either. The 47-year-old supervisory teacher did it in 12 days, spending just shy of 112 hours on his bike at an average speed of 15.6 mph from June 12 to 24.

On the last day, he knocked off 197 miles because he got lost the day before and ended up 16 miles off route.

Block had plenty of help along the way. His brother Charlie and his two sons, Isaac and Sam, were his support team, carrying gear and other supplies so Block could go light.

But most days, Block didn’t see his relatives for hours on end. They’d go sightseeing while he pedaled and pedaled and pedaled.

Block started out each day at dawn and rode 10 to 14 hours a day. It took four days to get across Montana. He rode south from Columbia Falls down Highway 83 to Highway 200 and then followed Highway 200 or took side routes close to it for nearly 1,000 miles.

Along the way, Block dodged a rattlesnakes, drilling rigs in the Bakken oil fields, a big bull buffalo in Theodore Roosevelt National Park, a live skunk, a dead porcupine and a deer that was hit by an oncoming car — just missing the spray of offal as the deer collided with vehicle.

He rode through thunderstorms and fierce headwinds and resorted to using diaper rash ointment to treat an awful road rash brought on by hour after hour on a narrow bike seat. Despite all the miles, he never got a flat tire.

“It was kind of a race against myself,” Block said.

As one might imagine, Block’s not an ordinary cyclist. He competes in triathlons and also enjoys climbing and hiking. He’s climbed every named peak in Glacier National Park except two — a spire on Dusty Star Mountain and the tallest Citadel Spire.

Back home, Block is now managing the Deer Park School, where enrollment has dropped from a little more than 50 students three years ago to 95 this year. In addition to being the supervisory teacher, he also teaches math. He’s taught there 18 years now.

When he’s not biking, he’s hiking or climbing or kayaking. Would he do the bike journey again?

“Sure,” he said. “But I’d shorten the mileage a little more. Enjoy it.”

When Block rolled into Watertown near dark on the last day, the sides of the road glowed with fireflies.

Block kept a journal of the trip. This is his last entry: “As my senses are recuperating, I ponder, was this bike tour a cure or part of the disease … I shudder…what’s next?”